Sound testing Form 1 cans?

[Kuraki]

I apologize if this has been asked/discussed before(tried to search, get no results, tried google, same), and I certainly don't want to open the can of worms surrounding testing of commercially produced suppressors, but, are there any affordable meters available to get approximate measures on their F1 cans?

I'm assuming the answer is no, just like finding an affordable high speed camera (which I'd probably rather have anyway, and spent more than enough time trying to find already.)

[Bendersquint]

I apologize if this has been asked/discussed before(tried to search, get no results, tried google, same), and I certainly don't want to open the can of worms surrounding testing of commercially produced suppressors, but, are there any affordable meters available to get approximate measures on their F1 cans?

I'm assuming the answer is no, just like finding an affordable high speed camera (which I'd probably rather have anyway, and spent more than enough time trying to find already.)

Unless you consider $5K affordable there are no meters out there that would get approx dB numbers.

[quietoldfart]

I was looking for an affordable high-speed camera for several years. Finally found one used for $100; a Sanyo Xacti HD1010. The 1920x1080 video at 60fps is way beyond my computer's ability to play back so I don't bother shooting that. Might some day if something comes along worth capturing in such high quality, and I can just play it back a few years later when I get a PC capable of displaying it. But mostly I shoot stills with it, and it's good for that. And the 300fps mode, with somewhat noisy but usable in good light 448x336 resolution, is about what I had been hoping for. It's fast enough that with good light it can capture an airgun pellet travelling about 500fps for a few frames in a side shot, and if shooting through a scope (making a mount for it was tricky, but worked) captures the whole flight path of a pellet doing 610fps out to at least 40 metres on a bright day. Really neat for analyzing recoil and such. And for the kid doing funny things, obviously.

It only grabs 10 second bursts, with no audio, but for $100 in as-new condition I am not complaining. Especially since the regular video modes have classic Xacti sound quality, which is to say delicious for a digicam. Gunshots actually sound like gunshots, no horrible auto noise filtering like most digital cameras seem to have. So many suppressor test videos are ruined by either that or by the idiots shooting at metal plates a few yards away... or both. A clean, unmodulated audio track is a fine thing to have in a video camera. It has a tiny remote, so it's easy to set it on a tripod and swivel the viewing screen towards you so you can see what's being captured while you shoot. Battery life is phenomenal, as in take it camping for a few days and shoot a lot of pictures and come home with half a battery charge still left. There's just so much good stuff about this camera. Except that Sanyo quit making the Xacti line of pistol grip cameras, dammit.

Anyway, on the sound meter Bendersquint is obviously correct. There's no cheap meter which can respond quickly enough to get an accurate measure of dB values. But my $16 meter from eBay does a very consistent job insofar as comparing sounds. I can smack a hammer against a metal plate and it'll tell me how much louder that is than my suppressor. And if I change the K baffles somehow, it'll show whether I've added or lost a couple of decibels. Reliably, one day to the next, in different rooms, with the numbers always remaining consistent for a given set of acoustical parameters. This is the model:
http://www.ebay.com/itm/9V-Digital-LCD- ... 418b432b09

When I got started building and testing suppressors for my little French semi-auto .22" pistol with its 7" barrel, I was at 13" for the tube with 4" over the barrel, no barrel ports, and with 7 long K baffles in front of the muzzle. The meter was showing about 112dB for Remington subsonics. Now that I have learned a lot more about baffle shaping and jetting and have a number of barrel ports with a better system of controlled pressure distribution over the barrel, the same ammunition is reading about 103 to 104dB with an 8" tube and 7 very small, nested K baffles. If I go back and test the long tube I'm back up to 110 or 111dB, the difference coming from the barrel porting as compared to my initial tests. I know that these numbers are not accurate by any stretch, but I also know that they are repeatable, and that has value for me. It confirms what my ears are telling me, which is that the early, long suppressor with relatively naive baffle shaping (1.25" long with a neck and relatively poor porting shapes and alignment) was significantly, even dramatically louder. Almost painful, but not quite. And when I use something like a CCI Quiet, the meter ranges from about 99dB in an acoustically dead room up to around 101.5dB for a very lively room with no padding. That relationship between ammunition types makes sense, and again is repeatable.

So is such a cheap toy valuable? Not to an industry professional like Bendersquint, obviously. But if you have access to commercial suppressors for tests on the same weapon with the same ammunition, the numbers you record from those could be of great use in developing your own baffle system and comparing the results. In my humble opinion. I don't believe it is a case of 'pay a minimum of $5,000 or go home and cry into your pillow' as so many nay-sayers around here seem to be suggesting. Neither are your numbers going to be something you can publish and boast about, obviously, as they're useless for comparison with other sorts of measurements. So a modest tool for in-house comparative testing, that's all.

[Capt. Link.]

Kuraki the best way is to compare what you have to a suppressor with posted numbers and use your friends ears to tell which is more quiet.The ear can detect minor changes in sound pressure and you will have a rough number that is fairly close.

These inexpensive meters are not useful tools as the peak sound pressure is over before the meter even begins to respond.Most of them are around 30db off to begin with and don't have the dynamic range necessary to measure a unsuppressed gunshot to a suppressed one.A sure indication is when you get a different reading between a acoustically dead room and one with hard reflective surfaces.It means that you are reading the echo not the shot!

You can't bend the laws of physics nor can you measure how high a mountain is if you can't see the top.

[CMV]

... or by the idiots shooting at metal plates a few yards away...

I resemble that remark.....

If you have a dealer in your area ask about comparing yours to commercial cans during their next demo event. I do a decent amount of business with 2 locally & don't think they'd say no if I asked.

Not scientific, not a true measurement, but you can gauge and have an observer gauge if the sound is appx louder, quieter, or the same. Reality is, who cares what it meters? How it sounds - TO YOU -is what's important.

[Kuraki]

Thanks guys

A friend on the local Sheriff's Dept once mentioned they have a sound meter for enforcing noise violations, but I wonder if it's just one of the cheaper units that can't really register what we'd be trying to measure.

As far as comparisons, it's really tough. Small town. I don't even know of anyone else who owns a single can, although I'm sure there are a couple around.

[Bendersquint]

Thanks guys

A friend on the local Sheriff's Dept once mentioned they have a sound meter for enforcing noise violations, but I wonder if it's just one of the cheaper units that can't really register what we'd be trying to measure.

As far as comparisons, it's really tough. Small town. I don't even know of anyone else who owns a single can, although I'm sure there are a couple around.

The PD meter WILL NOT do what you need it to do, its like comparing a minivan to a F1 racecar....sure they both have wheels and a driver but their purpose is completely different.